1. Field of the Invention
The present invention relates to a security technique that prevents illegal accesses to an output device connecting with a network, while ensuring convenience of output via the network.
2. Description of the Related Art
A variety of printers are used as an output device of computers. The printer is conventionally one-to-one connected to a computer via a specific cable like a two-way parallel interface (hereinafter referred to as ‘local connection’), and receives data from the computer to carry out printing. With recent advancement of LAN (Local Area Network), multiple printers connecting with a network share one or plural printers connected to the network.
Application of a certain protocol called IPP (Internet Printing Protocol) actualizes printing between an arbitrary client and an arbitrary printing apparatus, both connecting with the Internet. The IPP specifies an output resource with a URI (Uniform Resource Indicator) and actualizes printing via the Internet.
The recent development of the information infrastructure, such as the Internet, and the improvement in mobility of terminals used for access to the information infrastructure, such as mobile computers and cellular phones, enable access to information from any locations. In such circumstances, the technique of allowing free choice of the output resource for printing on the Internet has been highly demanded.
The high level of security is required in the system of printing via the Internet, in order to prevent illegal accesses to the printing apparatus. The printing apparatus used as the output resource is thus generally connected to the Internet via a security system called firewall.
The prior art security system, however, fails in sufficiently taking advantage of printing via the Internet.
In one practical example, it is assumed that a user makes an estimate sheet with a user's own computer and tries to print the estimate sheet in a customer's office. If a printer in the customer's office is connected to the Internet without any security system, the user can print the estimate sheet via the Internet by simply specifying the URI of the printer. In the actual situation, however, the security system is present to interfere with transmission of print data from the user's computer to the printer in the customer's office and prohibit printing.
Such a problem is not restricted to printing via the Internet but is commonly found in the case of utilizing a printing apparatus connected to any of diverse networks like an Intranet via the security system. This requirement is not restricted to printing but commonly arises in general output devices for images, documents, sound, and any other data.